exercise 1.shoppingcartapplication.java

son los ejercicios de ssd3 espero que les ayuden a algunos jeje se la pasan chido.....!!!!!!

import java.io.*;
import java.util.*;

/**
 * This is an application that adds products to an electronic shopping cart.
 * 
 * @author Neil
 * @version 1.0.0
 */
public class ShoppingCartApplication {

	private static BufferedReader stdIn = new BufferedReader(
			new InputStreamReader(System.in));
	private static PrintWriter stdOut = new PrintWriter(System.out, true);
	private static PrintWriter stdErr = new PrintWriter(System.err, true);

	private ShoppingCart cart;

	/**
	 * Starts application.
	 * 
	 * @param args not used.
	 * @throws IOException if error reading from standard input.
	 */
	public static void main(String[] args) throws IOException {

		ShoppingCartApplication application = new ShoppingCartApplication();

		application.run();
	}

	private void run() throws IOException {

		cart = new ShoppingCart();

		int choice = getChoice();

		while (choice != 0) {

			if (choice == 1) {
				cart.addProduct(readProduct());
			} else if (choice == 2) {
				stdOut.println(cart.toString());
			} else if (choice == 3) {
				stdOut.println(cart.getTotalValue());
			}

			choice = getChoice();
		}
	}

	private int getChoice() throws IOException {

		do {

			int input;

			try {
				stdErr.println();
				stdErr.print("[0]  Quit\n" + "[1]  Add Product\n"
						+ "[2]  Display Products\n" + "[3]  Display Total\n"
						+ "choice>");
				stdErr.flush();

				input = Integer.parseInt(stdIn.readLine());

				if (0 <= input && 3 >= input) {

					return input;

				} else {
					stdErr.println("Invalid choice:  " + input);
				}
			} catch (NumberFormatException nfe) {
				stdErr.println(nfe);
			}
		} while (true);
	}

	private Product readProduct() throws IOException {

		final String DELIM = "_";

		String name = "";
		int quantity = 0;
		double price = 0.0;

		do {
			
			try {
				stdErr.print("product  [name_qty_price]>");
				stdErr.flush();

				StringTokenizer tknzr = new StringTokenizer(stdIn.readLine(),
						DELIM);

				if (tknzr.countTokens() == 3) {
					name = tknzr.nextToken();
					quantity = Integer.parseInt(tknzr.nextToken());
					price = Double.parseDouble(tknzr.nextToken());

					if (quantity > 0 && price >= 0) {
	
						return new Product(name, quantity, price);
					} else {
						stdErr.println("Invalid input");
					}
				} else {
					stdErr.println("Invalid input");
				}
			} catch (NumberFormatException nfe) {
				stdErr.println(nfe);
			}
		} while (true);

	}
}